Adapting Sidechain Ducking to Target Bus Volume

FMOD Studio
1

Hi everyone,

I have a question about sidechaining, specifically spectral sidechaining, in the FMOD mixer.

I have an “Explosions” bus and a “Music” bus. I’ve set up a spectral sidechain modulator on the “Music” bus that receives sidechain input from the “Explosions” bus.

My question is: Is it possible to make the ducking effect adapt to the overall volume of the Music bus itself? I want the ducking to be less pronounced when the “Music” bus is already very quiet. Ideally, if the Music bus is almost silent, the ducking from the Explosions bus would be minimal or non-existent.

I noticed that it is possible to modulate the sidechain level based on the music bus, but only negatively. This means that the louder the music is, the less ducking will happen, which is the opposite of what I am trying to do.

I read in the documentation for sidechaining that " if the modulated property is measured in dB, the modulator can only lower it".

Is there another way to achieve what I am trying to do?

I’m using FMOD 2.03.06.

Thanks for any help!

2

Yes, this is possible.

If you look at the spectral sidechain modulator, you’ll see that it has an “Amount” property. This property defines the maximum amount by which the modulator can duck the signal. In your case, you want “Amount” to be high when the music is loud, and low when the music is quiet. To do this:

  1. Automate the value of “Amount” on a global parameter such that “Amount” is low when the parameter value is low, and high when the parameter value is high.
  2. Make the value of the global parameter change depending on how loud the signal in the music bus is. The easiest way to do this is to add a new non-spectral sidechain modulator to the global parameter’s value, and link it to a new sidechain on the music bus. (You’ll want to put this sidechain to the left of the fader, so that it isn’t affected by the ducking applied by the spectral sidechain modulator that’s already there). You’ll need to set the new modulator’s amount and threshold properties to correctly adjust the value of the global parameter, such that the global parameter’s value is high when the signal coming from the sidechain on the music bus is high, and low when the signal coming from the sidechain on the music bus is low.

Does using a non-sidechain modulator to modulate the a parameter that controls the amount property of your spectral sidechain modulator in this fashion get you the behavior you want?

3

Hi Joseph,
Thanks for your reply!

This seems very promising, I just think that I am doing one small step wrong. At the moment I can only modulate the Amount Property in a positive direction, I will try to explain bellow and hopefully you can see were I am going wrong.

These are the steps I’ve taken:

  1. Created a global parameter “MusicDuckingAmount” with ranges 0-10, default value 0
  2. Added a sidechain on the music bus that modulated the parameter value of “MusicDuckingAmount”, so that when the music is loud the parameter goes up in value.
  3. Modulate the amount of the spectral modulator with the value of “MusicDuckingParamter”.
  4. This seems to work when the amount on the spectral parameter when it is automated to a positive amount but not to a negative.
  5. I have tried to set the “MusicDuckingAmount” parameter to negative range as well, but it didn’t seem to change the behaviour.

I have attached a video in this post the hopefully makes it clearer. In the video I am modulating the frequency of a bandpass just to demonstrate that it works when positive but not negative at the moment. You will also hear a big impact sound, this sound is connected to the spectral sidechain.

Thanks for your help, again this seems like the exact thing I want to be able to do!

4

Hey again!

After some experimenting, I noticed that this setup you described works if the “Amount” of the EQ is being modulated by a normal sidechain and not a spectral sidechain.

The spectral sidechain works when modulation the “Amount” positively but not in the negative range. A normal sidechain can however modulate the “Amount” in the negative range.

With this setup I’m pretty sure I can achieve what I wanted to do.

I was wondering though if you know why the spectral sidechain can’t modulate the “Amount” in the negative range?

Thanks for all the help!